An apparatus having a wireless part instead of a wire part has recently become widespread. For example, a personal computer is connected to a printer by radio. An apparatus employing a radio communication standard called Bluetooth (BT) as a time division multiple access (TDMA) standard has become widespread. Bluetooth is defined by a standardization group called the Bluetooth Special Interest Group (Bluetooth SIG). Bluetooth is normalized for the purpose of interconnecting a notebook-sized personal computer, a personal digital assistant (PDA), and a cellular phone without using a cable to communicate sound or data.
The BT standard, which is a unified standard, employs the same signal format independently of a manufacturer of the apparatus. In other words, the signal format is not flexible and thus improvement of communication quality and communication distance are largely restricted.
Therefore, a radio communication apparatus is also developed which has both a Bluetooth system and a telephone system, and includes a cellular phone or a telephone set of a company's own cordless phone standard that additionally has a Bluetooth standard communication function. A Bluetooth radio unit (BT radio unit) and a cordless phone unit (CDL radio unit) are individually disposed for responding to radio signals with different standards in the prior art. This structure, however, leads to the enlargement of the apparatus and the cost increase.